This title appears in the Scientific Report : 2013 

High-speed chemical imaging system based on front-side-illuminated LAPS
Itabashi, Akinori
Kosakab, Naoki / Miyamotoa, Ko-ichiro (Corresponding author) / Wagner, Torsten / Yoshinobua, Tatsuo / Schöning, Michael J.
Bioelektronik; PGI-8
Bioelektronik; ICS-8
Sensors and actuators / B, B 182 S. 315-321
Amsterdam [u.a.] Elsevier Science 2013
Journal Article
Physics of the Cell
Sensorics and bioinspired systems
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The chemical imaging sensor is a semiconductor-based chemical sensor that can visualize the spatial distribution of specific ions on the sensing surface. The conventional chemical imaging system based on the light-addressable potentiometric sensor (LAPS), however, required a long time to obtain a chemical image, due to the slow mechanical scan of a single light beam. For high-speed imaging, a plurality of light beams modulated at different frequencies can be employed to measure the ion concentrations simultaneously at different locations on the sensor plate by frequency division multiplex (FDM). However, the conventional measurement geometry of back-side illumination limited the bandwidth of the modulation frequency required for FDM measurement, because of the low-pass filtering characteristics of carrier diffusion in the Si substrate. In this study, a high-speed chemical imaging system based on front-side-illuminated LAPS was developed, which achieved high-speed spatiotemporal recording of pH change at a rate of 70 frames per second. © 2013 Elsevier B.V. All rights reserved.